Location estimation of UWB-based wireless capsule endoscopy using TDoA in various gastrointestinal simulation models

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Wireless Communications

Background:

• Wireless capsule endoscopy (WCE) is vital for diagnosing gastrointestinal disorders.
• Accurate localization of WCE is critical for effective treatment planning.
• Ultra-Wide Band (UWB) technology offers promising advancements for WCE positioning.

Purpose of the Study:

• To investigate the effectiveness of the Chan algorithm using Time Difference of Arrival (TDoA) for WCE localization.
• To analyze the impact of receiver configuration and abdominal tissue variations on positioning accuracy.
• To reduce the Root Mean Square Error (RMSE) in WCE location estimation.

Main Methods:

• Utilized the Chan algorithm with TDoA for WCE positioning.
• Conducted UWB propagation experiments using human voxel models in an electromagnetic simulation environment.
• Applied distance errors derived from simulated abdominal tissue thickness to the Chan algorithm.
• Evaluated performance with varying numbers of receivers and compared results to the Cramér-Rao lower bound (CRLB).

Main Results:

• Positioning receivers in three rows reduced estimation error by 44%; a middle reference receiver reduced it by 33%.
• Increasing receivers from 9 to 33 decreased RMSE from approximately 4 mm to 1 mm.
• The Chan algorithm with TDoA demonstrated improved accuracy in WCE localization, especially with optimized receiver placement.

Conclusions:

• The TDoA-based Chan algorithm, enhanced by UWB and optimized receiver configurations, significantly improves WCE localization accuracy.
• This approach holds potential for developing more precise and reliable futuristic endoscopic capsules.
• Accounting for abdominal tissue variations further refines positioning accuracy, crucial for clinical applications.